Clamping means having a clamping position and an open position for material in thread, ribbon or strip form serve in knitting machines and looms for clamping the free end of a thread coming from a supply spool for as long as the clamped thread is not needed for a knitting or weaving operation for which it has to be drawn from the supply spool.
Most of the known clamping means contain a clamping pin under spring bias, by means of which the thread is pressed against a clamping surface (e.g., German Offenlegungsschrift Nos. 23 25 747 and 24 10 415, or German Auslegeschrift No. 16 35 868). Owing to the fact that these clamping means consist of a plurality of parts, and a relatively complex opening and closing mechanism is needed to operate them, they are unsuitable especially when it is important to accommodate them within a very small amount of space. Other known thread clamping means operate by vacuum (German Auslegeschrift No. 11 48 347) and therefore they are suitable as a rule only when they can be mounted in a stationary manner.
In a number of applications, especially in knitting machines of the kind designated in the generic part of claim 10, a plurality of relatively small thread carriers is provided, which circulate on an endless path and release the thread at the beginning of a working section so that it can be laid in the knitting needles and looped. At the end of the work section, the thread is cut by a cutting means and the thread end is clamped and carried back along a return run to the beginning of the working run. In these cases, too, the clamping means are relatively costly clamping pins which take up a great deal of space and whose operation is complex (e.g., German Offenlegungsschrift Nos. 23 51 741 and 25 31 734).